A turbine blade that is mounted in a jet engine or the like is exposed to a high-temperature gas environment. For this reason, as a countermeasure against heat, a structure has been proposed in which the turbine blade is made to be hollow with a blowout port provided in the trailing edge, and by supplying cooling air to the interior of the turbine blade, the air is made to be blown out from the blowout port. In a turbine blade that adopts this structure, the blowout port is formed by notching a portion of the front-side wall of the turbine blade, and the trailing edge portion that becomes the highest temperature is reduced in thickness. The trailing edge undergoes film cooling by blowing out the cooling air while causing it to flow along the inner wall surface of the back-side wall that is exposed to the blowout port.
Also, Patent Document 1 and Patent Document 2 provide art that improves the heat transfer coefficient from the turbine blade to the cooling air by providing recesses or the like in the inner wall surface of the back-side wall that is exposed by the aforementioned notching.
Moreover, Patent Document 3 provides art that improves the heat transfer coefficient from the turbine blade to the cooling air by providing recesses or the like in the inner wall surface of the back-side wall in the interior of a turbine blade.